cover slip vs sheet glass

cover slip and sheet glass both are nouns.

Word	Noun	Adjective	Verb	Adverb
cover slip	Yes	No	No	No
sheet glass	Yes	No	No	No

As nouns, sheet glass is a hypernym of cover slip; that is, sheet glass is a word with a broader meaning than cover slip:

cover slip: a small and very thin piece of glass used to cover the specimen on a microscope slide
sheet glass: glass formed into large thin sheets

Other hypernyms of cover slip include plate glass.

cover slip (noun)	sheet glass (noun)
a small and very thin piece of glass used to cover the specimen on a microscope slide	glass formed into large thin sheets